WASHINGTON, June 24 (Reuters) - A GlaxoSmithKline Plc plant in Canada that makes the flu vaccine Flulaval has been cited by the U.S. Food and Drug Administration for failing to meet quality control standards.

GSK said it is working to rectify the problems and does not expect a delay in distributing the vaccine for the 2014-2015 flu season. The company typically starts shipping the product at the end of July.

In a warning letter dated June 12 to GSK's flu vaccine manufacturing facility in Ste-Foy, Quebec, the FDA said the company failed to take appropriate steps to prevent microbiological contamination of products, among other violations.

GSK said on Tuesday no contaminated products had been released to the public.

"Every batch of GSK vaccines is subject to extensive review before it is released," the company said. "Vaccines that do not pass this rigorous review are discarded."

The FDA said controls for the purified water system at the plant were inadequate and that some Gram-negative bacteria identified in water used for equipment washing had been implicated in product contamination issues at the facility as far back as 2011. (http://1.usa.gov/1jL3UUS).

In 2011, 24 vaccine lots were rejected due to the excessive presence of endotoxins. These are found in the cell walls of Gram-negative pathogens such as salmonella. When bacteria die the endotoxins are released, possibly contaminating laboratory equipment and causing health problems in people and animals.

Other lots were rejected in March and July 2012, and certain test lots were contaminated last year. These were manufactured on the same equipment as commercial lots for release to the United States, the FDA said in its warning letter.

This year, 20 of the lots manufactured, or 21 percent, showed bacterial growth and endotoxin levels. These lots were also rejected. GSK said the lots were rejected as part of the company's quality review process.

The FDA said there was no set schedule for disinfection of the water system and that manufacturing controls in place were inadequate to control bacteria on unsterilized surfaces. The agency said the company's investigation into the repeated accumulations of bacteria had been inadequate.

The deficiencies, the FDA said in its letter, "are an indication of your quality control unit not fulfilling its responsibility to assure the identity, strength, quality, and purity of your licensed biological drug product and intermediates."

GSK said it anticipates providing between 28 and 33 million doses of flu vaccine to the United States for the upcoming season and said it is working with health agencies in Canada and the United States to "support their efforts in managing supply of influenza vaccines for the 2014-15 flu season." (Reporting by Toni Clarke in Washington and Esha Dey in Bangalore; Editing by Sriraj Kalluvila, Marguerita Choy and Paul Simao)

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